Fertility problems and Abortion Flashcards
Name 4 general causes of sub-optimal reproductive performance in sheep
1) Anestrus / low ovulation rate
2) fertilization failure
3) embryonic loss / early fetal death
4) late fetal loss (abortion/preg tox)
Name 3 common causes of poor ram breeding soundness
1) Testicular degeneration / hypoplasia
2) epididymitis
3) scrotal trauma
Causes of epididymitis in the UK
gram negative pleomoprhic bacteria (actinobacillus seminis, hemophilus somnus, histophilus ovis)
ascending urogenital infections
CS epididymitis
Palpable abnormalities (firm nodules in epididymis; testicular atrophy) on routine breeding soundness exam
+/- swelling, pain, lameness, inapettance during acute infections
Epididymitis Tx
Cull
What is normal gestation length?
~147 days (142-150)
Target abortion percentage?
<2%
Name a viral cause of abortion in sheep
Border disease virus
Name 2 protozoan causes of abortion in sheep
Toxoplasma gondii, neospora caninum
What are the 2 most commonly diagnosed causes of ovine abortion?
Toxoplasma gondii and Chlamydophila abortus
Name 5 bacterial causes of abortion in sheep
Chlamydophila abortus (enzootic abortion) campylobacter species salmonella leptospira iterrogans listeria monocytogenes
Name some non-infectious causes of abortion in sheep (8)
nutrition, pregnancy toxemia, stress, vaccination, transport, dog worry, pasteurellosis, chronic fluke
What is the best type of sample to submit to investigate abortion problems?
whole fetus / placenta
What are 5 measures that should be taken after an abortion (but before confirmation of cause is found)?
1) Isolation and marking of aborted ewes
2) prompt disposal of products of abortion
3) biosecurity to avoid spread
4) hygienic precautions to minimize zoonoses
5) reduced stocking density or pregnant lambing ewes (if practical)
CS of chlamydial abortion?
in last 3 weeks of pregnancy, healthy ewes, reddish vaginal discharge, lambs freshly dead or alive (but weak and unable to suckle)
Dx of chlamydial abortion?
Placentitis - discoloration/ necrosis of cotyledons, edema/rough thickening of intercotyledonary membranes, yellow/pink pus-like exudate
demonstration of large # of chlamydial elementary bodies in ZN stained smears of placental tissue
or paired serology if no aborted material
What are the outcomes of chlamydial infection for:
1) Late pregnant/non-pregnant ewes?
2) ewe in first half of pregnancy?
3) surviving lamb from infected ewe?
1) no immune response, abortion during last 3 weeks of NEXT pregnancy
2) abortion during last 3 weeks of CURRENT pregnancy
3) abortion during it’s first pregnancy
Control of chlamydial abortions?
isolate aborted ewes + surviving lambs (cull)
remove products of abortion and contaminated bedding
Abx tx of whole flock or in-contact ewes (oxytet)
vaccination
Chlamydial vaccination: what kind, when, result?
Live attenuated vaccines
vaccinate all ewes in first ear; then replacment ewes/gimmers before mating
in outbreak, may reduce but not eliminate the risk of abortion in following year
CS of toxoplasma abortions? (early, mid, late pregnancy)
Early pregnancy = embryonic death / resorption (barren ewes)
mid-pregnancy = fetal death (mummification); fetal growth retardation
Late pregnancy = freshly dead lambs; weak live lambs
Dx of Toxoplasma
Aborted material gross findings: placenta (hyperemic cotyledons, small white foci of necrosis & calcification), lamb (SQ edema; fibrinous exudate in pleural & peritoneal cavities)
Confirmation = histo and serology
Serology in aborted ewes w/ toxo: what do high and low titers mean?
High titers = usually consistent w/ recent infection
Low titers = only indicate infection @ some stage in the past - Ab can persist for several years
Tx and control of toxoplasma
Rodent control, keep feed stores safe from cats, limit cat breeding
Decoquinate - 2mg/kg SID (last 2 weeks of pregnancy)
Vaccination (toxovax) - live vx, single dose 3 weeks before mating
How long after infection w/ campylobacter will the ewe abort?
7-25 days after
